Modulation Of Chemokine And Chemokine Receptor Expression Following The Infection Of IEC Cells With PEDV

Porcine Epidemic Diarrhea(PED)is an acute infectious disease caused by Porcine Epidemic Diarrhea Virus(PEDV)that causes atrophy of the intestinal villi and impairs intestinal function,causing a serious block on the steady development of the pig industry.Since 2010,the variant PEDV strains have emerged and become prevalent,making the clinical vaccine efficacy of existing vaccines unsatisfactory.In order to be able to effectively control the occurrence of PED,it is necessary to further explore the molecular pathogenic mechanism of PEDV.Chemokines mediate cell recruitment to sites of inflammation and are influenced by,and influence,the production of cytokines.Since the IEC cell line provides a relevant in vitro model system for porcine intestinal pathogen-host cell interactions,the modulation of chemokine responses following infection of porcine IEC cells PEDV isolates was studied to indicate how this may be involved in the induction of pathogenesis and of effective immune responses.In the present study,the expression of six chemokines CCL2,CCL3L1,CCL5,CXCL2 and CXCL8 as well as five chemokines receptors CCR1,CCR5,CCR7,CXCR3,CXCR4 was evaluated in IEC infected with PEDV compared with mock-infected control samples at 12,24,36 hours post-infection(hpi).Real-time quantitative PCR assay indicated that CCL2,CCL3L1 and CCR1 expression levels were significantly upregulated in the first 12 hpi,however the mRNA levels were down regulated at 24 and 36 hpi,whereas CXCR4 and CCL5 mRNA levels were down streamed at 12 and 24 hpi then overexpressed at 36 hpi.mRNA levels of CXCL2,CXCL8,CXCL10,CCR5,CCR7 and CXCR3 were significantly reduced in supernatants from infected at 12,24 and 36 hpi,with different levels of down expression for each.The data shows that infection of IEC with PEDV provoke either down-regulation or not up-regulation of chemokines and its receptors.This may be significant for the initiation of an effective and protective immunity.The results may provide new visions to considerate the title role of chemokines in PEDV pathogenesis.For more understanding of the role of these chemokines and its receptors we recommend more research about the migration of immune system cells meditated by these chemo-attractants.